The present invention relates to a technique that is effectively applied to an atmospheric pressure, elevated temperature desorption apparatus which increases the temperature of a plate-like solid sample (semiconductor wafer, optical disc, etc.) and desorb impurities (substances of an extremely small amount) that are absorbed in or on the surface of the solid sample into a carrier gas under an atmospheric pressure.
In semiconductor manufacturing technologies, among apparatuses for analyzing impurities (substances of an extremely small amount) absorbed in or on the surface of a semiconductor wafer that has been subjected to respective manufacturing processes, there is known, for instance, an ultra-high vacuum, elevated temperature desorbed gas analyzing apparatus that is described in Vacuum, Vol. 34, No. 11 (1991), pp. 813-819. In this ultra-high vacuum, elevated temperature desorbed gas analyzing apparatus, a semiconductor wafer is divided into small square sections of 1 cm.times.1 cm and their temperature is elevated in an ultra-high vacuum chamber, and gases desorbed from the semiconductor wafer are analyzed.
As another example, there is known a sample column that is described on Page 61 of "Out Gas Free Resist Process," VLSI Ultra-clean Technology Workshop No. 5, Ultra-clean Resist Processing, Jun. 28, 1990. In this apparatus, a semiconductor wafer is divided into small strips and their temperature is elevated under the atmospheric pressure, and gases desorbed from the semiconductor wafer are analyzed.
However, the conventional techniques have the following problems.
(1) When a semiconductor wafer is divided into small square sections or strips, contaminants (other impurities) attach to the semiconductor wafer. Therefore, the quantitative analysis of impurities originally absorbed in or on the surface of the semiconductor wafer cannot be performed correctly.
(2) When a semiconductor wafer is introduced into a chamber, the external air flows into the chamber to cause contaminants (other impurities) to stick to the inside of the chamber. Therefore, the quantitative analysis of impurities originally absorbed in or on the surface of the semiconductor wafer cannot be performed correctly.
(3) Since there occurs variations in a temperature distribution of a heated semiconductor wafer, the quantitative analysis of impurities originally absorbed in or on the surface of the semiconductor wafer cannot be performed correctly.
(4) Since the front surface and the back surface of a semiconductor wafer cannot be processed separately, the quantitative analysis of impurities originally absorbed in or on the front surface of the semiconductor wafer cannot be performed.
(5) When a semiconductor wafer is moved into a chamber from each manufacturing process, the semiconductor wafer is contaminated by the air. Therefore, the quantitative analysis of impurities originally absorbed in or on the surface of the semiconductor wafer cannot be performed correctly.